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Bio theory Flashcards

Papers 1-11 + m/j 2024 + chap

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1
Q

Difference between trace during exercise and rest

A

hmemrfo

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2
Q

Outline how the body removes an oxygen debt.

A

Lactic acid is broken down by combining it with oxygen in the liver. The liver cells do this by aerobic respiration. Breathing rate and heart rate remains high= More oxygen faster.

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3
Q

Explain why some parts of a plant can act as both a source and a sink.

A

(acts as a ) source when it is (moving sucrose from) a region of
production / photosynthesising ;
(acts as a ) sink when it is, growing / storing / respiring / a region of
utilisation ;

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4
Q

The rate of oxygen production was assumed to be the same as the rate of photosynthesis.
Suggest why the rate of oxygen production was not the same as the rate of photosynthesis.

A

Oxygen is used in respiration. The rate of photosynthesis may appear lower than it actually is.

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5
Q

What does specificity mean?

A

(the enzyme) only able to act on a particular (specific) substance

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6
Q

Explain how vaccination protects people against a transmissible disease such as measles.

A

1 harmless / dead pathogen is given ;
2 antigens are present on pathogens ;
3 (antigens) trigger an immune response ;
4 lymphocytes produce antibodies ;
5 ref. to specificity ;
6 memory cells are produced ;
7 antibodies destroy pathogen ;
8 providing active immunity

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7
Q

Explain why the total biomass of the snakes is less than the total biomass of the mice.

A

1 snakes occupy a higher trophic level than mice ;
2 (most of the) energy is lost between the trophic levels ;
3,4 examples of energy loss (lost in exretion eg: urine)
5 not enough energy to sustain larger biomass at higher trophic levels

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8
Q

Define the term diffusion.

A

The net movement of particles from a region of higher concentration to lower concentration caused by the random movement of particles

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9
Q

Describe the function of chlorophyll.

A

Chlorophyll transfers light energy to chemical energy to make starch in photosynthesis.

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10
Q

Describe the disadvantages of genetically modifying crops.

A

1 (additional) nutrient / energy, content may be (too) small ;
2 seeds may be expensive to purchase ;
3 farmers unable to save seeds ;
4 ref. to side effects / (unknown) health risks, to consumers ;
5 risk of cross-contamination with wild rice ;
6 reduction, in biodiversity / genetic diversity ;
7 consumers won’t buy GM products / ethical concerns ;

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11
Q

Eggs contain protein.
Describe how the biological washing powder removes egg stains.

A

+chemical digestion

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12
Q

Outline the roles of bile in the body. (Two points)

A

Bile emulsifies lipids (fats and oils) for faster breakdown by lipase by increasing the surface area of the lipids. Bile neutralises the stomach to provide optimum ph for enzymes.

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13
Q

Describe the negative impacts to an ecosystem of large-scale monocultures.

A

-Loss of biodiversity
-Habitat destruction
-Soil infertility
-Soil erosion
-Increased pollution from run-off
-land could have been used for food prod

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14
Q

Suggest why selective breeding should continue for many generations. Explain why scientists do this before selling them to farmers.

A

Reduce variation to maintain the desirable feature. They need to build up a large amount of seeds to sell to farmers. Ensures that the variety can grow in field conditions.

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15
Q

Explain the role of hydrochloric acid in the alimentary canal.

A

Found in the stomach. Provides ph of 2 which kills harmful microorganisms in the food and provides the optimum for protease.

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16
Q

Explain the risks to these species of birds that have decreasing populations.

A

The birds have an increased risk of ‘extinction, because of less genetic ‘variation, so they are less able to adapt to change in the ‘environment. (eve)

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17
Q

Explain the advantages of the double circulation of the mammal.

A

-Allows high blood pressure in the body -Efficient oxygen supply to the body —- -Allows more time for gas exchange
- prevents damage to lungs, lower pressure

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18
Q

Describe the role of progesterone in pregnancy.

A

Maintains the thickness of uterus lining. Inhibists FSH and LH secretion. Prevents ovulation.

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19
Q

Describe why conservation projects such as seed banks are important.

A

maintaining / increasing biodiversity ;
(moral) responsibility to save other species ;
protect / maintain
ecosystems ;
by supporting recycling of nutrients ;
by supporting flow of energy in, food chains / food webs ;
reduce (plant) extinction ;
preventing loss of animal species that depend on plant species ;
possible genes ;
possible drug sources ;
possible crop plants / selective breeding ;
allows for future research ;

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20
Q

Outline the process of artificial insemination.

A

Sperm is collected and inserted into the reproductive parts of female, eg: vagina at the time of their reproductive cycles when they are producing gametes

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21
Q

Ways of conservation of a species

A

providing, habitats / protected areas ;
(laws to) prevent / limit, hunting / poaching ;
education ;
(captive) breeding programmes / use of AI ;

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22
Q

Describe the expected appearance of a cell from a potato cube that has been immersed
in distilled water for 30 minutes.

A

Turgid, cell contents presses the cell wall.

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23
Q

Outline how the carbohydrates made during photosynthesis are used in plants.

A

Glucose used to release energy,

converted to and stored as starch ;

converted to sucrose, sent to sink(s) ;
sucrose in nectar to attract pollinators ;
fructose / sucrose in fruits to attract animals ;

(glucose) converted to cellulose to build cell walls ;
lignin for cell walls ;

glucose used to make, amino acids / fatty acids ;

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24
Q

Explain why body cells can have different specialised functions even though they contain the
same genes.

A

Not all genes are expressed. Cells only produce the specific proteins they need.

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25
Q

Define allele

A

Alternate form of a gene

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26
Q

Mutation causes formation of new alleles which increases genetic variation.
State two other sources of genetic variation in populations.

A

Meiosis
Random mating
Random fertilisation

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27
Q

Explain the structural adaptations of arteries and veins.

A

arteries:
1 thick, muscular, wall to withstand the high blood pressure and is muscular to change it;
2 wall contains elastic tissue to stretch and recoil due to changing pressure ;
3 small, lumen maintains high blood pressure ;

veins:
4 large lumen to provide less resistance for blood flow and to carry larger volume of blood ;
5 thin walls so blood is moved by contraction of surrounding muscle
6 valves to prevent backflow

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28
Q

Features of monocotyledons
{6 points}

A

one cotyledon ; parallel veins ; roots directly from the stem ; flower parts in multiples of three ; vascular bundles in stem arranged randomly ;
narrow leaves ;

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29
Q

Describe what is meant by the term species.

A

A group of organisms that can reproduce to produce fertile offspring.

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30
Q

Advantages of self-pollination
{4 points for both (self adv.), 2 disadv. for cross}

A

1 more chance of successful pollination ;
2 less pollen wasted ;
3 less need for pollinators (bees) and pollen
4 pollination can occur in plants that become isolated
(as occurs within same plant) ;
5 advantage to, farmers  in maintaining (named) selected varieties / limiting variation (from one generation to the next) ;

Cross disadvantages: more energy required, two parent plants required (still need to find cross adv.)

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31
Q

Disadvantages of self-pollination
{5 points}

A

1 less, variation / (genetic) diversity ;
2 limited ability to, adapt more slowly to (named) change in environment ;
3 more chance of, genetic / inherited, disease ;
4 fewer individuals survive (new infectious) diseases ;
5 more competition between plants (as have similar adaptations) ;

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32
Q

Explain why the area above the girdle in Fig. 4.1 will become swollen.
Use the terms source and sink in your answer.

A

1 glucose made in leaves, converted to sucrose and is translocated in the phloem
2 leaves act as a source and roots act as a sink ;
3 sucrose, collect above the girdle ;

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33
Q

The DNA and Plasmid combo forms..

A

a recombinant

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34
Q

Apart from structural features, state five reasons why bacteria are useful for genetic modification.

A

reproduce rapidly ;
no ethical  / welfare, issues ;
ability to make complex molecules ;
easy to maintain or store/ don’t take up too much space ;
share a genetic code with other (named) organisms ;
offspring are genetically identical
presence of plasmids

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35
Q

Which kingdom does bacteria belong to?

A

Prokaryotes.

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36
Q

[The different kingdoms]
What do I use to remember the ‘often contain chloroplasts’?

A

Orange
Umbrellas
Make
Stupid
Umbrellas + cell structure, multi or uni

Two of them belong to protocists

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37
Q

Give 3 points about the plant kingdom.

A
  • feed by photosynthesis
  • have cellulose cell walls and often have chloroplasts
  • may have roots, stems and leaves
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38
Q

Give 3 points about the fungus kingdom.

A
  • feed by digesting organic waste and absorbing it into their cells.
  • usually multicellular
  • have cell walls
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39
Q

Give 3 points about protoctist kingdom.

A
  • feed by photosynthesis or organic substances
  • multi-cellular or uni-cellular
  • may have cell wall or chloroplasts
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40
Q

Give 5 points about prokaryotes.

A
  • some photosynthesis
  • usually unicellular (unlike fungi which are usually multi) (have cellwalls though)
  • have a circular loop of DNA free in the cytoplasm
  • often have plasmids
  • no mitochondria
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41
Q

Nitrogen gas is converted into a more reactive form.

A

Nitrogen fixation

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42
Q

Amino acids from decomposing plants are released as ammonium ions.

A

Deamination

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43
Q

Outline the dangers of non-biodegradable plastic waste to marine animals.

A

does not break down ;

idea that ability to breathe affected ;
idea that ability to move affected ;
idea that ability to gain nutrition affected ;
injury/death ;

toxic / poisonous ;

blocks light producers, cannot photosynthesise ;
(so) less energy enters food webs ;

loss of (named), habitat / feeding / breeding area ;
more likely to be predated ;
idea that (plastic) accumulates up the food chain ;

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44
Q

Describe how the DNA and gene form a recombinant plasmid.

A

The same restriction enzyme…so that the sticky ends have complementary base pairs and can join together by using DNA ligase.

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45
Q

Explain the reason for constantly rotating plant A.

A

negating the effect of gravity, on one side of the plant (only) ;
(used as a control) to compare with (the response of) plant
B ;

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46
Q

Explain the plant hormone process.

A

Auxin is prod in the tip and diffuses down the shoot. It collects on one side of the plant and stimulates cell elongation. The plant grows, bending upwards.

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47
Q

Explain why the egg cell contains stores of protein and fat.

A

The stores provide energy for mitosis. Protein makes the cytoplasm and enzymes.

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48
Q

Describe how an embryo is formed from a zygote.

A

A zygote divides by mitosis. This is repeated again and again, forming a ball of stem cells which are genetically identical.

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49
Q

What does a diaphragm do?

A

Changes the volume of the thorax

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50
Q

What does the spinal cord do?

A

coordinates responses

connects CNS and PNS

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51
Q

What does a relay neuron do?

A

connects neurons, transmits impulses

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52
Q

What does the trachea contain?

A

contains cilia to move mucus out of the airway

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53
Q

Where would a receptor molecule for a neurotransmitter
be found on a motor neuron?

A

Tip of dendrite

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54
Q

Explain how the neuron is adapted for transmitting impulses.

A

1 axons long, to transmit impulse, over long distance
2 many branches to connect to relay, neurones / 
cells / effector / muscle ;
3 mitochondria to release energy, for, transmission of
impulse / protein synthesis / active transport / making or
releasing neurotransmitters ;
4 vesicles to, carry / release neurotransmitters into synapse ;
5 receptor molecules, to allow signal to be received by next neurone

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55
Q

Amylase:

organ where
enzyme is
secreted

organ where
the enzyme
acts

products of
digestion

A

salivary
glands

mouth

 maltose

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56
Q

Pepsin:

organ where
enzyme is
secreted

organ where
the enzyme
acts

products of
digestion

A

stomach

stomach

amino acids

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57
Q

lipase:

organ where
enzyme is
secreted

organ where
the enzyme
acts

products of
digestion

A

pancreas

small intestine
/ duodenum
/ ileum

fatty acids and
glycerol

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58
Q

Maltase:

organ where
enzyme is
secreted

organ where
the enzyme
acts

products of
digestion

A

small intestine

epithelial lining
of the small
intestine

glucose

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59
Q

Chemical fertilisers have helped farmers to increase food production.
Discuss the negative impact on the natural environment of using chemicals, other than
fertilisers, in modern farming methods.

A

1 pesticides / insecticides / herbicides:
2 kill, non-target species (in natural environment) ;
3 example of specific impact from harm of non-target
species ;- disturbs flow of energy
4 loss of biodiversity / disrupt food chains ;
5 ref to resistant organisms or super, bugs / weeds ;
6 pollute / destroy / AW, non-target / named, area / habitat ;
7 (antibiotics cause) antibiotic-resistance ;

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60
Q

State what is meant by a monoculture.

A

an area of ground covered in a single crop in production with almost no other species present

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61
Q

State the process which can be used to develop crop plants that can produce proteins
from other species.

A

genetic modification

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62
Q

Explain how cells in plants keep them upright.

A

plants have cell walls ;

pressure of water pressing against cell wall / ref. to turgor ;

ref. to xylem (offering support) ;

MP4 e.g. ref. to lignin

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63
Q

State the type of microorganism that contains chlorophyll.

A

some protocists

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64
Q

Suggest why the researchers determined the concentration of chlorophyll rather than
counting the number of microorganisms in the sample.

A

organisms too small, so difficult to count

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65
Q

Using the information in Fig. 5.3, identify the day when the water was the most transparent.

A

biggest gap between depth and chlorophyll concentration

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66
Q

Explain why the transparency of the water is important for organisms that contain
chlorophyll.

A

to absorb / receive, (enough) light (energy) ;
(light) is necessary for photosynthesis ;
(for the organisms) to make sugars / starch / to convert light
(energy) into chemical energy ;

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67
Q

Explain the consequences of the death of these organisms to the lake ecosystem.

A

1 eutrophication ;
2 increase in bacteria which are decomposers ;
3 decomposers respire aerobically ;
4 decomposition causes a reduction in (dissolved) oxygen ;
5 (reduced oxygen) causes death of fish / (named aquatic)
animals
6 (death of producers means) less food for consumers / loss
of biodiversity

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68
Q

List structural adaptations of insect-pollinated flowers.

A

2024 answer:
stigmas / style / carpel, within flower ;
anthers / stamens, within flower;
conspicuous, large, colourful petals form a landing platform ;
spotted pattern (to attract insects) ;

2022:
nectar ;
spiky pollen ;
sticky stigma ;

strongly scented
often have nectaries at the base of petals
large quantities of pollen

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69
Q

State morphological features that can be used to distinguish flowering plants from
ferns.

A

flowers, fruit, leaves, pollen, ovules

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70
Q

State what protein biotechnologists will use to increase the volume of juice produced from
pear fruit.

A

pectinase

71
Q

State the function of mitochondria

A

aerobic respiration

72
Q

State one feature of plants that is used to distinguish them from fungi.

A

cell wall in plants are cellullose
(fungi are made of chitin)

presence of chloroplasts

73
Q

Yeast is a fungus that can respire to produce ethanol.
State the balanced chemical equation for this type of respiration in yeast.

A

C6H12O6 → 2C2H5OH + 2CO2

74
Q

aerobic respiration chemical equation

A

C6H12O6 + 6 oxygen = 6 carbon dioxide + 6 water

75
Q

photosynthesis chemical equation

A

aerobic respiration reversed

76
Q

anaerobic for humans

A

glucose = lactic acid

77
Q

(To do with the effect of sugar on respiration in yeast cells)
Suggest the reason for the oil layer in the apparatus shown in Fig. 1.1.

A

prevent oxygen from entering

allowing carbon dioxide to escape

77
Q

State one reason why no more carbon dioxide gas was produced after 35 minutes by the yeast in a sugar solution, shown in Fig. 1.2

A

sugar has been used up

78
Q

State one way in which humans use the carbon dioxide gas produced by yeast cells.

A

to make dough rise

79
Q

State the name of one gas, other than carbon dioxide, that contributes to the enhanced
greenhouse effect.

A

methane

80
Q

Define sense organ

A

a group of receptor cells that are able to respond to a specific stimulus

81
Q

Describe how the events that occur at a synapse generate an impulse in the next neuron.

A

Neurotransmitter molecules released from vesicles into synaptic gap.

Neurotransmitters diffuse across gap and bind to receptor proteins on the next
neurone. This triggers an electric impulse in the next neurone.

82
Q

accomodation

A

changing the shape of the lens to focus on an object at different distances from the eye (rpt) (csf) (folk and far NOT together) + light is focused onto the retina

83
Q

Describe the distribution and function of rods and cones in the eye.

A

distribution:
1 both found in retina
2 high concentration of cones / no rods, are found in the fovea
3 nothing at blind spot

function:
4 both detect light (are receptor cells)
5 rods respond to dim light and give black
and white image ;
6 cones respond to bright light and detect colour

84
Q

State the events in the life cycle diagram for organism 1 that would not be present
in a life cycle diagram for asexual reproduction.

A

formation of gametes, fertilisation

85
Q

Limiting factors for rate of photosynthesis.

A

light intensity, CO2 concentration, temperature, stomata (number of chloroplasts, water)

86
Q

What does the cervix do?

A

dilates in the process of birth

87
Q

What does the oviduct do?

A

site of fertilisation

88
Q

What does the uterus lining do?

A

site of implantation

89
Q

Describe the function of the placenta in humans.

A

1 gas exchange: oxygen transfers to fetus from mother / carbon dioxide transfers to
mother transfers from fetus ;
2 transfers of (dissolved) nutrients, from maternal / to fetal
(circulation);
3 transfer of excretory products, from fetal / to maternal
(circulation) ;
4 (transfer of nutrients / excretory products) by diffusion ;
5 secretes progresterone
6 passive immunity provided (to fetus) ;
7 separates fetal and maternal blood supply ;

90
Q

State two functions of the amniotic fluid that is found in the amniotic sac.

A

1 provides support to fetus ;
2 protect fetus from (mechanical) shock ;
3 maintains temperature (of fetus) ;
4 allows movement (of fetus) / allows for development of
bones and muscles;
5 prevents dehydration ;
6 ref. to swallowing of (amniotic) fluid / involved in digestive tract development / involved in lung development ;
7 provides sterile environment ;

91
Q

Describe the pathway taken by the products of protein digestion from the villi to the liver.

A

move into capillaries in villi then are carried in (blood) plasma and travel to the
hepatic portal vein ;

92
Q

Describe what is meant by the term catalyst.

A

A catalyst is a substance that increases the rate of reaction and is not used up in the reaction.

93
Q

Explain how the body provides a suitable pH for lipase activity.

A

Bile is an alkaline liquid produced in the liver and stored in the gall bladder. Bile neutralises the gastric juices, which results in a suitable pH for lipase activity.

94
Q

The valves in the heart.

A

Between the atrium and ventricle: (atrioventricular valves) bicuspid and tricuspid (right)

semi-lunar: ones at the top, prevent backflow

95
Q

Arota transports blood from the … to the …

A

left ventricle; rest of the body

96
Q

State two uses of water in a plant.

A
  • water is needed for photosynthesis
  • act as a solvent for transportation in plant
  • germination
  • for support
  • medium for metabolic reactions (chemical)
97
Q

when:
ovulation (egg is released) is most likely to occur ……………………………………………………….
shedding of the uterine lining occurs. ……………………………………………………..

A

LH is high, usually 12,13,14,15, or 16

when hormones are on the low, 1-8

98
Q

Describe the role of FSH in the menstrual cycle.

A

stimulates ovaries to release of oestrogen ;
stimulates eggs to, mature / develop (in the ovary) ;

99
Q

State a conclusion for the results shown in Table 5.1 and Table 5.2. (Plants in North America compared to Europe)

A

greater leaf area

100
Q

Explain how the monkey flower plants have developed a larger leaf area over time.

A

Mutation causes variation in a species. The plants were in competition for resources such as light. Plants with larger leaf area are better adapted, because larger leaves absorb more sunlight.

Plants with larger leaves survived and reproduced, passing on the large leaf alleles to its offspring. This occurs over many generations until larger leaves are common in population. This process is called natural selection.

101
Q

State the names of two processes that add carbon dioxide to the atmosphere.

A

respiration ;
combustion ;
decomposition 

102
Q

Describe the effect on the environment of additional carbon dioxide in the atmosphere.

A

CO2 is a greenhouse gas which contributes to global warming. The sea level rises.. Weather events are more often and stronger eg: … With more CO2, the effects of global warming will worsen even further.

103
Q

State two advantages of using a pyramid of energy rather than a pyramid of biomass to
represent a food chain.

A

shows actual energy transfer ;
time is taken into account ;
more accurate ;

104
Q

Explain one way that fishing can be managed to conserve fish stocks.

A

closed seasons ;
protected areas ;
quotas ;
education ;
smaller nets ;
larger mesh size ;
monitoring / legislation ;

= prevents overfishing and allows fish to breed

105
Q

Define tissue. Give an example.

A

group of similar cells that work together to perform a particular function; EG: layer of cells lining the stomach which make enzymes

106
Q

What does the muscle tissue in the stomach do?

A

makes the wall of the stomach move in and out, churning the food and mixing it up with enzymes

107
Q

What is the palisade tissue in plants specialised for?

A

carry out photosynthesis

108
Q

What do ciliated cells do?

A

lining the trachea and bronchi of animals, moves mucus upwards

109
Q

Define bacteria. What’s one strange thing about them?

A

unicellular organisms whose cells do not contain a nucleus, no mitochondria or chloroplast but do photosynthesise

110
Q

What is the circular loop of DNA in bacteria aka?

A

bacterial chromosome

111
Q

What is an organ?

A

a group of tissues that work together to perform a particular function (several organs for organ system)

an onion bulb is even an organ

112
Q

Define active transport

A

the movement of molecules or ions through a cell membrane from a region of lower concentration to a region of higher concentration (against the concentration gradient) using energy from respiration

112
Q

Define double circulatory system

A

a system in which blood passes through the heart twice on one complete circuit of the body

113
Q

Define gene

A

a length of DNA that codes for one protein

114
Q

Define chromosome

A

a length of DNA found in the nucleus of a cell; it contains genetic information in the form of many different genes

115
Q

Define hormone

A

chemicals that are produced by a gland and carried in the blood, which alter the activities of their specific target organs

116
Q

homeostasis definition

A

the maintenance of a constant internal environment

117
Q

Define population

A

a group of organisms of one species, living in the same area at the same time

118
Q

Define excretion

A

the removal of waste products of metabolism and substances in excess of requirements

119
Q

Discuss heart muscles

A

atria receive blood, but ventricles pump blood so they have thicker, more muscular walls. the left ventricle has an especially thick wall to pump blood to the rest of the body

120
Q

Describe how coronary arteries can get blocked.

A

Cholesterol deposits buid up inside the walls of arteries which make the artery wall stiffer and the lumen narrower, so it is more difficult for blood to flow through. Blood clots can form. Cardiac muscle does not get oxygen…heart stops beating (muscle cells cannot respire aerobically)

This is called CHD

121
Q

How to reduce chances of getting CHD?

A

-do not smoke cigarettes
-taking care of diet: saturated fats is higher in meat than in plant-based foods, so plant oils instead. Eat fast food in moderation considering this
–regular exercise (keeps you fit, prevents excessive weight gain, deceases blood pressure, clears mind, causes chemical release in brain that increase feelings of well-being)

122
Q

How can you hear a heartbeat?

A

using a stethoscope

123
Q

What does ECG stand for?

A

electrocardiograph

124
Q

How is the crazy swing of valves prevented?

A

tendons attached to valves stop them from swing too far, they have to be stopped in the closed position

125
Q

How do capillaries perform their function?

A

Walls are thin so substances can get in and out easily, smallest capillary wall is only one cell thick.
allows delivery of named useful substances to tissues and removal of named waste ;
small lumen ;
short diffusion distance ;
slows down blood flow to maximise time for diffusion ;
gaps between capillary cells ;

126
Q

… is squeezed by leg muscles when walking. This helps to push blood back up to your heart

A

large veins

127
Q

Explain the blood vessel situation with the liver.

A

hepatic artery supplies oxygen, hepatic portal vein brings blood from the digestive system, all the blood leaves in the hepatic veins

128
Q

What is a lesser known function of white blood cells?

A

clear up any dead body cells

129
Q

Explain the process of phagocytis.

A

taking bacteria or other small structures into a cell’s cytoplasm, and digesting them with enzymes

130
Q

Explain why a leaf is considered to be an organ.

A

it is made of (named) tissues (in a leaf) ;
(tissues), working together / for a specific (named) function(s) ;

131
Q

Explain how the palisade mesophyll is adapted.

A
  • cells tightly packed
  • positioned right below upper epidermis for light to reach chloroplasts
  • vacuole keeps many chloroplasts towards the sides of the cells
132
Q

Explain how the spongy layer is adapted.

A
  • air spaces to allow diffusion of carbon dioxide and evaporation from cell surfaces
133
Q

State the main function of the stomata.

A

Gas exchange. Diffusion of co2 in and oxygen out. Regulation of transpiration.

134
Q

Predict and explain the effect of high humidity on the stomata.

A

reduces stomatal closure, reduced water vapour diffusion gradient, so gaurd cells do not lose water as much as in the first experiment.

135
Q

Explain how proteins are made by a cell.

A
  1. mRNA is copied from a gene
  2. mRNA moves out the nucleus, to the cytoplasm
  3. mRNA passes through the ribosome
  4. ribosome makes proteins by assembling amino acids in an order determined by the base sequence of the mRNA
  5. Protein synthesis uses energy
136
Q

State two types of cell membrane proteins.

A

carriers ;
receptor(s) (proteins) ;
maltase / enzyme ;

137
Q

Suggest reasons for the decrease in the number of bacterial infections resistant to erythromycin from 1993 to 1995.

A

*fewer doses used
*new vaccines and antibiotics used
*use antibiotics when essential eg: not for viral infections
*awareness of antibiotic resistance
*improved detection
*population reached herd immunity
*isolating infected individuals

138
Q

Explain how bacteria become resistant to antibiotics.

A

-mutations occur (in some of the bacteria) ;
-(genetic) variation increases ability of bacteria to survive antibiotic
treatment ;
-bacteria with (antibiotic) resistance, survive / reproduce ;
pass on resistant allele to offspring
-increase in frequency of resistant, allele (in the population) ;
ref to natural selection / become (better) adapted (for the new
environment) ;

139
Q

Some bacteria have a flagellum.
State the function of a flagellum.

A

movement/swimming

140
Q

4th consumer is called?

A

quarternary consumer

141
Q

Outline how the energy in the primary consumers in this aquatic food web is used to produce biomass in the secondary consumers.

A

Primary consumers contain chemical energy which is transferred to secondary consumers when they are eaten. Food particles are digested to make glucose available for respiration. Energy is used in protein synthesis for growth.

142
Q

Define decomposer.

A

an organism that gets its energy from dead organic material

143
Q

State the name of the growth responses observed in the bean roots and shoots.

A

upwards or downwards, positive or negative gravitropism

144
Q

Shoot is growing straight…

A

auxin is evenly distributed in the shoot

145
Q

Suggest why oxygen and water are required for germination.

A

(oxygen) aerobic respiration ;
(water) used in (named) cell process ;
(water) is a solvent ;
(water) used for turgor ;

146
Q

The ………….. produces trypsin which breaks down protein in
…………. pH conditions. These conditions are created by a substance called ………… , which neutralises the gastric juices and also has an important role in the …………… of fats and oils.

A

The (small intestine) produces trypsin which breaks down protein in
(alkaline) pH conditions. These conditions are created by a substance called (bile), which neutralises the gastric juices and also has an important role
in the (emulsification) of fats and oils.

147
Q

State two visible features that distinguish the fish from the amphibian.

A

Fish have fins and scaly skin

148
Q

Describe the similarities and the differences between the circulatory systems of the fish and
the amphibian

A

1 both have, heart / blood vessels / capillaries / arteries / veins ;
2 (heart with) one ventricle / no (visible) septum ;
3 both have valves (in the heart) ;
4 blood flows through atrium and then ventricle ;

6 fish have capillaries in gills and amphibians have capillaries in lung and skin ;
7 fish have a single circulatory system and amphibians have a (incomplete)
double circulatory system ;
8 fish has a 2-chambered heart / amphibian has 3-chambered heart ;
9 amphibians have two atria / fish have one atrium ;
10 amphibians have a separate circuit to the, gas exchange surface ;
11 fish have one valve (in heart) / amphibians have three valves (in heart) ;

149
Q

Describe how humans maintain a constant body temperature when the external
temperature decreases.

A

1 (internal temperature is maintained by) homeostasis
2 external temperature detected by, (thermo)receptors / sensory neurones in the skin ;
3 impulses (via sensory neurones) to the brain,
impulses from brain travel along motor neurone to effectors to cause a response.

4 change in internal temperature is detected by the brain, hypothalamus
5 (nerve) impulses are sent (via motor neurones) to (effectors in) the skin ;

Hair erector muscles contract. Hairs trap a layer of air which acts as insulation. Fatty tissue as well. Muscles contract and relax fast to release heat. Arterioles vasoconstriction to decrease blood flow to the surface, decreases heat loss. Sweat gland stops sweat production.

150
Q

Role of fat layer?

A

insulation and energy reserve

151
Q

Role of temperature receptors?

A

detect temperature changes

152
Q

Explain the reasons for the difference in the numbers of mitochondria and chloroplasts
between the root hair cell and the palisade cell.

A

mitochondria:
1 more in root hair cell
2 aerobic respiration ;
3 to, release energy ;
4 for active, transport
5 against, a concentration gradient ;

chloroplasts:
6 in palisade only
7 no light reaches root hair cells / cells are underground or in soil ;
8 photosynthesis
9 contain chlorophyll ;
10 transfers energy from light to, energy in chemicals
11 to synthesise, glucose

153
Q

Describe the results.

A

COICC

  1. Conclusion: enzyme activity increases with temperature.
  2. Overall: enzyme activity is higher when enzyme solution concentration is higher.
  3. Individual: activity increases steeply then decreases, peaks, no records.
  4. Comparison: cases remained the same while population fluctuated, delay
  5. Changes: small changes after pH10, steepest change at 7-9, gradient changes
154
Q

Explain the results.

A

CHD
1. Conclusion: increases as decreases
2. How: by increased transpiration
3. Details: describe everything, CO2 is required, light provides energy for photosynthesis

155
Q

Sexual reproduction advantages.

A

1 allows genetic variation ;
2 (allows expression of) different combinations of alleles ;
3 allows adaptation in response to, changing environment
4 reduces chances of extinction / increases chance of survival ;

Animals: example of adaption advantage
Plants: population less susceptable to pest or disease, genetic diseases less likely, seed dipersal means less competition

156
Q

Sexual production disadvantages.

A

1 requires two, parents
2 requires, (named) pollinators ;
3 takes longer / is slower ;
4 idea that the increased genetic variation means that some plants
might be less adapted to the environment
5 more energy required

157
Q

The dot on the villi is a cell which secretes mucus, what is it?

A

goblet cell

(ciliated cells lining the trachea and bronchi of animals sweep mucus upwards)

(cilia are tiny projections from some of the cells in the lining of the respiratory passages, cilia of many adjacent cells beat rhythmically)

158
Q

places in the body where goblet cells are found

A

trachea, bronchi, bronchioles

159
Q

Define stem cell

A

unspecialised cells that are able to divide by mitosis to produce different types of specialised cells and that can become specialised

160
Q

Explain the differences in the average number of mitochondria in each type of cell. (heart muscle, red blood cell, epithelium in small intestine)

A

1 mitochondria are site of aerobic respiration ;
2 release energy ;

3 intestine (cells), respire more ;
4 epithelial cells need more energy ;
5 active transport in the small intestine ;
6 heart (cells) (continuously) contract ;

7 red blood cells need space, for haemoglobin 
8 red blood cells, are moved in the blood
9 RBC take up oxygen by diffusion so no energy needed for active transport, so good if RBCs do not use up the oxygen they transport ;

161
Q

State two features of amphibians that distinguish them from all other vertebrates.

A

eggs laid in water, larvae live in water while adults live on land

larvae have gills while adults have lungs

moist, slimy, smooth skin

162
Q

Big round parts of frog eye..
Shield part of frog eye..

A

..pupil
..cornea

163
Q

(rods and cones)
round part of neurone..
body part of neurone..
outside body part..

A

nucleus
cytoplasm
cell membrane

164
Q

Suggest how the number and distribution of rod cells and cone cells across the retina of a nocturnal mammal would differ from a human retina.

A

more rods present and less cones
rods at fovea
(more rod in the middle)

165
Q

Mitosis is a type of nuclear division which produces genetically identical cells.
It is important for growth, ………………….. of tissues and ……………….. reproduction.
Just before mitosis the chromosomes are replicated and then the chromosomes
………………… so that the chromosome number is maintained in each daughter cell.

Meiosis is another type of nuclear division that is involved in the production of gametes. The chromosome number is halved from ……………….. to haploid resulting in genetically different cells. The fusion of the nuclei of two gametes formed by meiosis forms a ……………….. . This process is known as
……………………… .

A

Mitosis:

repair of tissues
asexual
separate

Meiosis:

halved from diploid
zygote
fertilisation

166
Q

Describe what is meant by a gene mutation.

A

random change in a gene; random changes in the base sequence of DNA; can produce new alleles

167
Q

How can mutation rates be increased?

A

ionising radiation and chemicals such as lead and mercury

168
Q

Describe and explain how fish stocks can be managed sustainably sustainably and how overfishing can be prevented through conservation.

A

quotas, closed seasons, protected areas, ban harmful net types such as dredging nets, restriction on net mesh size, inspectors monitor catches in fishing boats
(mention of conservation points) **captive breeding

169
Q

that identify the processes that:

  • release the most energy per glucose molecule ………………………………….
  • take place in yeast cells. ……………………………………………………………..
A

aerobic respiration

aerobic respiration and anaerobic respiration

170
Q

What is the mineral ion used to make amino acids in plants?

A

nitrate ions

171
Q
A

Bio MC (7 decks)

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